SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0864803a60582508972a7de848d2ae7f44ed5d0b251327f0411de5334cb263cd' 
  AND token = 'tCzGrToOWcYQKDKkUMunz7gGUvdXFOD7VUgaVgBZv7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}